1. Field of Invention:
The present invention relates to thermal processing of semiconductor devices and, more particularly, is directed towards a method and apparatus involving pulsed light beam localized thermal processing of semiconductor devices.
2. Description of the Prior Art:
Thermal processing has become a widely employed fabrication technique in the manufacture of semiconductor devices such as diodes, transistors, solar cells, integrated circuits and the like. Examples of commonly employed thermal processes include diffusion of dopant elements into semiconductor materials, annealing of crystalline structure after mechanical or radiation induced damage, annealing and electrical activation of dopant atoms after ion implantation, sintering of metallic and dielectric coatings to improve mechanical and optical properties.
Although it is desirable to influence only specific local regions of the device during individual processing steps, usually the regions in the vicinity of the surface, conventional thermal processing is performed by elevating the temperature of the entire device structure and by maintaining the temperature environment for an adequate period of time to produce the required thermal effects. Generally, thermal processing is performed in a furnace type facility for times ranging from a few minutes to several hours at temperatures less than 200.degree. C. to temperatures above 1000.degree. C. Such techniques, in addition to being time and energy consuming, have had limited application due to the fact that many materials and device structures degrade as a result of the thermal exposures necessary for the processes. A need exists for an improved method and apparatus for rapid thermal processing of specific regions of a semiconductor device that does not cause deleterious effects in the region being processed and that does not significantly alter other regions of the semiconductor material.